001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.camel.impl; 018 019import java.io.IOException; 020 021import org.apache.camel.CamelContext; 022import org.apache.camel.Component; 023import org.apache.camel.NoFactoryAvailableException; 024import org.apache.camel.spi.ComponentResolver; 025import org.apache.camel.spi.FactoryFinder; 026import org.apache.camel.util.ResolverHelper; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030/** 031 * The default implementation of {@link ComponentResolver} which tries to find 032 * components by using the URI scheme prefix and searching for a file of the URI 033 * scheme name in the <b>META-INF/services/org/apache/camel/component/</b> 034 * directory on the classpath. 035 * 036 * @version 037 */ 038public class DefaultComponentResolver implements ComponentResolver { 039 040 public static final String RESOURCE_PATH = "META-INF/services/org/apache/camel/component/"; 041 042 private static final Logger LOG = LoggerFactory.getLogger(DefaultComponentResolver.class); 043 044 private FactoryFinder factoryFinder; 045 046 public Component resolveComponent(String name, CamelContext context) { 047 // lookup in registry first 048 Component componentReg = ResolverHelper.lookupComponentInRegistryWithFallback(context, name); 049 if (componentReg != null) { 050 return componentReg; 051 } 052 053 // not in registry then use component factory 054 Class<?> type; 055 try { 056 type = findComponent(name, context); 057 if (type == null) { 058 // not found 059 return null; 060 } 061 } catch (NoFactoryAvailableException e) { 062 return null; 063 } catch (Exception e) { 064 throw new IllegalArgumentException("Invalid URI, no Component registered for scheme: " + name, e); 065 } 066 067 if (getLog().isDebugEnabled()) { 068 getLog().debug("Found component: {} via type: {} via: {}{}", new Object[]{name, type.getName(), factoryFinder.getResourcePath(), name}); 069 } 070 071 // create the component 072 if (Component.class.isAssignableFrom(type)) { 073 return (Component) context.getInjector().newInstance(type); 074 } else { 075 throw new IllegalArgumentException("Type is not a Component implementation. Found: " + type.getName()); 076 } 077 } 078 079 private Class<?> findComponent(String name, CamelContext context) throws ClassNotFoundException, IOException { 080 if (factoryFinder == null) { 081 factoryFinder = context.getFactoryFinder(RESOURCE_PATH); 082 } 083 return factoryFinder.findClass(name); 084 } 085 086 protected Logger getLog() { 087 return LOG; 088 } 089 090}